[MIPS] Fix build issue with browser tests when using mipsel-nacl-clang

Remove options that were valid for pnacl toolchain but are not valid for
mipsel-nacl-clang.
This fixes the build issues:

 mipsel-nacl-clang: error: unsupported option '--pnacl-mips-bias'
 mipsel-nacl-clang: error: unsupported option '--pnacl-allow-translate'

Review URL: https://codereview.chromium.org/1806403002

Cr-Commit-Position: refs/heads/master@{#381801}

chrome/test/data/nacl/nacl_test_data.gyp

@@ -896,18 +896,6 @@
             'sources': [
               '<(DEPTH)/native_client/tests/stubout_mode/partly_invalid.c',
             ],
-            'conditions': [
-              ['target_arch=="mipsel"', {
-                'compile_flags': [
-                  '--pnacl-mips-bias',
-                  '-arch', 'mips32',
-                  '--pnacl-allow-translate',
-                ],
-                'link_flags': [
-                  '--pnacl-allow-native',
-                ],
-              }],
-            ],
           },
         },
       ],