glsl/tests/optimization-test: correctly set compare_ir

Now that we have srcdir we can use it to correctly manage/point to the
script. Effectively fixing OOT invokation of `make check'.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

src/compiler/glsl/tests/optimization-test.sh

@@ -1,11 +1,5 @@
 #!/bin/sh
 
-if [ ! -z "$srcdir" ]; then
-   compare_ir=`pwd`/tests/compare_ir.py
-else
-   compare_ir=./compare_ir.py
-fi
-
 if [ -z "$PYTHON2" ]; then
     PYTHON2=python2
 fi
@@ -29,6 +23,8 @@ if [ -z "$srcdir" -o -z "$abs_builddir" ]; then
     abs_builddir=`pwd`/../../
 fi
 
+compare_ir=$srcdir/glsl/tests/compare_ir.py
+
 total=0
 pass=0