Workaround for an uninitialized variable warning in the latest Clang

See https://github.com/flutter/flutter/issues/182781

Change-Id: I60dd936750a997f691d31c9eb28b48630360da88

src/libANGLE/validationEGL.cpp

diff --git a/src/libANGLE/validationEGL.cpp b/src/libANGLE/validationEGL.cpp
index f69bd95..397ac43 100644
--- a/src/libANGLE/validationEGL.cpp
+++ b/src/libANGLE/validationEGL.cpp
@@ -7087,7 +7087,7 @@
             break;
         default:
         {
-            EGLint querySurfaceValue;
+            EGLint querySurfaceValue = 0;
             ANGLE_VALIDATION_TRY(
                 ValidateQuerySurface(val, dpy, surfaceID, attribute, &querySurfaceValue));
         }