[SPARK-48128][SQL] For BitwiseCount / bit_count expression, fix codegen syntax error for boolean type inputs

### What changes were proposed in this pull request?

This PR fixes an issue where `BitwiseCount` / `bit_count` of boolean inputs would cause codegen to generate syntactically invalid Java code that does not compile, triggering errors like

```
 java.util.concurrent.ExecutionException: org.codehaus.commons.compiler.CompileException: File 'generated.java', Line 41, Column 11: Failed to compile: org.codehaus.commons.compiler.CompileException: File 'generated.java', Line 41, Column 11: Unexpected token "if" in primary
```

Even though this code has test cases in `bitwise.sql` via the query test framework, those existing test cases were insufficient to find this problem: I believe that is because the example queries were constant-folded using the interpreted path, leaving the codegen path without test coverage.

This PR fixes the codegen issue and adds explicit expression tests to ensure that the same tests run on both the codegen and interpreted paths.

### Why are the changes needed?

Fix a rare codegen to interpreted fallback issue, which may harm query performance.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Added new test cases to BitwiseExpressionsSuite.scala, copied from the existing `bitwise.sql` query test case file.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes apache#46382 from JoshRosen/SPARK-48128-bit_count_codegen.

Authored-by: Josh Rosen <joshrosen@databricks.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

Author: JoshRosen

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/bitwiseExpressions.scala

@@ -229,7 +229,7 @@ case class BitwiseCount(child: Expression)
   override def prettyName: String = "bit_count"
 
   override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = child.dataType match {
-    case BooleanType => defineCodeGen(ctx, ev, c => s"if ($c) 1 else 0")
+    case BooleanType => defineCodeGen(ctx, ev, c => s"($c) ? 1 : 0")
     case _ => defineCodeGen(ctx, ev, c => s"java.lang.Long.bitCount($c)")
   }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/BitwiseExpressionsSuite.scala

@@ -134,6 +134,47 @@ class BitwiseExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
     }
   }
 
+  test("BitCount") {
+    // null
+    val nullLongLiteral = Literal.create(null, LongType)
+    val nullIntLiteral = Literal.create(null, IntegerType)
+    val nullBooleanLiteral = Literal.create(null, BooleanType)
+    checkEvaluation(BitwiseCount(nullLongLiteral), null)
+    checkEvaluation(BitwiseCount(nullIntLiteral), null)
+    checkEvaluation(BitwiseCount(nullBooleanLiteral), null)
+
+    // boolean
+    checkEvaluation(BitwiseCount(Literal(true)), 1)
+    checkEvaluation(BitwiseCount(Literal(false)), 0)
+
+    // byte/tinyint
+    checkEvaluation(BitwiseCount(Literal(1.toByte)), 1)
+    checkEvaluation(BitwiseCount(Literal(2.toByte)), 1)
+    checkEvaluation(BitwiseCount(Literal(3.toByte)), 2)
+
+    // short/smallint
+    checkEvaluation(BitwiseCount(Literal(1.toShort)), 1)
+    checkEvaluation(BitwiseCount(Literal(2.toShort)), 1)
+    checkEvaluation(BitwiseCount(Literal(3.toShort)), 2)
+
+    // int
+    checkEvaluation(BitwiseCount(Literal(1)), 1)
+    checkEvaluation(BitwiseCount(Literal(2)), 1)
+    checkEvaluation(BitwiseCount(Literal(3)), 2)
+
+    // long/bigint
+    checkEvaluation(BitwiseCount(Literal(1L)), 1)
+    checkEvaluation(BitwiseCount(Literal(2L)), 1)
+    checkEvaluation(BitwiseCount(Literal(3L)), 2)
+
+    // negative num
+    checkEvaluation(BitwiseCount(Literal(-1L)), 64)
+
+    // edge value
+    checkEvaluation(BitwiseCount(Literal(9223372036854775807L)), 63)
+    checkEvaluation(BitwiseCount(Literal(-9223372036854775808L)), 1)
+  }
+
   test("BitGet") {
     val nullLongLiteral = Literal.create(null, LongType)
     val nullIntLiteral = Literal.create(null, IntegerType)