Fix Regex in DebugShaderPrecisionTest.

One regex had an extra parenthesis. Also confirms that we can use raw
string literals to produce more readable regexes.

Bug: angleproject:3162
Change-Id: I82e6bc622a8fa3d9f6424c53cb7dcb4dddde368a
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1821938
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

src/tests/compiler_tests/DebugShaderPrecision_test.cpp

diff --git a/src/tests/compiler_tests/DebugShaderPrecision_test.cpp b/src/tests/compiler_tests/DebugShaderPrecision_test.cpp
index b390bae..d5fbde4 100644
--- a/src/tests/compiler_tests/DebugShaderPrecision_test.cpp
+++ b/src/tests/compiler_tests/DebugShaderPrecision_test.cpp
@@ -306,7 +306,7 @@
         foundInHLSLCode("float4 angle_compound_add_frm(inout float4 x, in float4 y) {\n"
                         "    x = angle_frm(angle_frm(x) + y);"));
     ASSERT_TRUE(foundInAllGLSLCode("angle_compound_add_frm(_uv, angle_frm(_uu2));"));
-    ASSERT_TRUE(foundInHLSLCodeRegex("angle_compound_add_frm\\(_v(\\d)*, angle_frm\\(_u2\\)\\);"));
+    ASSERT_TRUE(foundInHLSLCodeRegex(R"(angle_compound_add_frm\(_v(\d)*, angle_frm\(_u2\)\);)"));
     ASSERT_TRUE(notFoundInCode("+="));
 }
 
@@ -1055,7 +1055,7 @@
         "}\n";
     compile(shaderString);
     ASSERT_TRUE(foundInAllGLSLCode("modf(angle_frm(_uu), _uo)"));
-    ASSERT_TRUE(foundInHLSLCodeRegex("modf\\(angle_frm\\(_u\\), _o(\\d)*)"));
+    ASSERT_TRUE(foundInHLSLCodeRegex(R"(modf\(angle_frm\(_u\), _o(\d)*)"));
 }
 
 #if defined(ANGLE_ENABLE_HLSL)