fix 31012 allow noEmitOnError with isolatedModules

fix microsoft#31012

Since the purpose of isolatedModules: true is to
do extra validation to ensure that separate
compilation is safe

Allowing emit in the presence of errors is
compatible with that intention.

Author: mheiber

src/compiler/program.ts

@@ -2707,10 +2707,6 @@ namespace ts {
                     createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, getEmitDeclarationOptionName(options), "isolatedModules");
                 }
 
-                if (options.noEmitOnError) {
-                    createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, "noEmitOnError", "isolatedModules");
-                }
-
                 if (options.out) {
                     createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, "out", "isolatedModules");
                 }

tests/baselines/reference/isolatedModulesNoEmitOnError.errors.txt

@@ -0,0 +1,5 @@
+//// [file1.ts]
+export var x;
+
+//// [file1.js]
+export var x;