build with assertions changed to an explicit opt in

the change in mx_graalpython.py makes BUILD_NATIVE_IMAGE_WITH_ASSERTIONS
false by default
while previously it defaulted to the CI flag

the change in python-gate.libsonnet aims to enable the assertions flag
for all non-benchmarking gates

additionally aligned the uses of the one argument version of
get_boolean_env instead of an explicit False as the second arg

Author: ovasicek

ci/python-gate.libsonnet

@@ -359,7 +359,11 @@
     //------------------------------------------------------------------------------------------------------------------
     // graalpy gates
     //------------------------------------------------------------------------------------------------------------------
-    local base_gate = $.os_arch_jdk_mixin + task_spec({
+    local base_gate = $.os_arch_jdk_mixin + task_spec(evaluate_late("_4_build_with_assertions", {
+        environment+: {
+            BUILD_WITH_ASSERTIONS: "true",
+        },
+    })) + task_spec({
         // private
         tags:: self.task_name,
         task_name:: null,

mx.graalpython/mx_graalpython.py

@@ -149,8 +149,8 @@ def get_boolean_env(name, default=False):
 CI = get_boolean_env("CI")
 GITHUB_CI = get_boolean_env("GITHUB_CI")
 WIN32 = sys.platform == "win32"
-BUILD_NATIVE_IMAGE_WITH_ASSERTIONS = get_boolean_env('BUILD_WITH_ASSERTIONS', CI)
-GRAALPY_WITH_BOUNCYCASTLE = get_boolean_env("GRAALPY_WITH_BOUNCYCASTLE", False)
+BUILD_NATIVE_IMAGE_WITH_ASSERTIONS = get_boolean_env('BUILD_WITH_ASSERTIONS')
+GRAALPY_WITH_BOUNCYCASTLE = get_boolean_env("GRAALPY_WITH_BOUNCYCASTLE")
 
 mx_gate.add_jacoco_excludes([
     "com.oracle.graal.python.pegparser.sst",
@@ -2709,7 +2709,7 @@ def graalpy_abiflags(*_):
 
 
 def dev_tag(_=None):
-    if not get_boolean_env('GRAALPYTHONDEVMODE', False) or 'dev' not in SUITE.release_version():
+    if not get_boolean_env('GRAALPYTHONDEVMODE') or 'dev' not in SUITE.release_version():
         mx.logv("GraalPy dev_tag: <0 because not in dev mode>")
         return ''