Update spirv-as invocations

After SPIRV-Tools commit 2e0f4b52 ("tools: refactorize tools flags
parsing. (#5111)", 2023-02-27), spirv-as needs to be told explicitly
when reading from stdin.

Author: svenvh

test/GroupAndSubgroupInstructions.spvasm

@@ -31,7 +31,7 @@
 ; spirv-dis tmp.spv -o llvm-spirv/test/GroupAndSubgroupInstructions.spvasm
 
 ; REQUIRES: spirv-as
-; RUN: spirv-as < %s --target-env spv1.0 -o %t.spv
+; RUN: spirv-as %s --target-env spv1.0 -o %t.spv
 ; RUN: spirv-val %t.spv
 ; RUN: llvm-spirv -r -emit-opaque-pointers %t.spv --spirv-target-env=CL1.2 -o %t.bc
 ; RUN: llvm-dis %t.bc -o %t.ll

test/spirv-tools-dis.ll

@@ -1,6 +1,6 @@
 ; RUN: llvm-as %s -o %t.bc
 ; RUN: llvm-spirv %t.bc --spirv-tools-dis -o - | FileCheck %s
-; RUN: llvm-spirv %t.bc --spirv-tools-dis -o - | spirv-as
+; RUN: llvm-spirv %t.bc --spirv-tools-dis -o - | spirv-as -
 
 ; Verify that the --spirv-tools-dis options results in SPIRV-Tools compatible assembly.