Auto merge of #13502 - servo:osmesa-debug, r=Ms2ger

Fix OS-Mesa discovery in debug mode.

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13502)
<!-- Reviewable:end -->

1 files changed, 2 insertions, 2 deletions

diff --git a/python/servo/testing_commands.py b/python/servo/testing_commands.py
index f990fbf9ec2..5f7a9e1fd1d 100644
--- a/python/servo/testing_commands.py
+++ b/python/servo/testing_commands.py
@@ -434,7 +434,7 @@ class MachCommands(CommandBase):
         # add it to the dynamic linker search path.
         if sys.platform.startswith('linux'):
             try:
-                args = [self.get_binary_path(True, False)]
+                args = [self.get_binary_path(kwargs["release"], not kwargs["release"])]
                 osmesa_path = path.join(find_dep_path_newest('osmesa-src', args[0]), "out", "lib", "gallium")
                 os.environ["LD_LIBRARY_PATH"] = osmesa_path
                 os.environ["GALLIUM_DRIVER"] = "softpipe"
@@ -444,7 +444,7 @@ class MachCommands(CommandBase):
                 pass
         if sys.platform.startswith('darwin'):
             try:
-                args = [self.get_binary_path(True, False)]
+                args = [self.get_binary_path(kwargs["release"], not kwargs["release"])]
                 osmesa_path = path.join(find_dep_path_newest('osmesa-src', args[0]),
                                         "out", "src", "gallium", "targets", "osmesa", ".libs")
                 glapi_path = path.join(find_dep_path_newest('osmesa-src', args[0]),