CDRIVER-5873 remove Debian 9 tasks from legacy config (#1846)

Author: eramongodb

.evergreen/generated_configs/legacy-config.yml

@@ -16403,15 +16403,6 @@ buildvariants:
   - install-libmongoc-after-libbson
   tags:
   - pr-merge-gate
-- name: clang38
-  display_name: clang 3.8 (Debian 9.2)
-  expansions:
-    CC: clang
-  run_on: debian92-test
-  tasks:
-  - release-compile
-  - debug-compile-nosasl-nossl
-  - .latest .nossl
 - name: openssl
   display_name: OpenSSL / LibreSSL
   run_on: archlinux-build
@@ -16459,15 +16450,6 @@ buildvariants:
   - debug-compile-sasl-openssl
   - .authentication-tests .openssl
   - .latest .nossl
-- name: gcc63
-  display_name: GCC 6.3 (Debian 9.2)
-  expansions:
-    CC: gcc
-  run_on: debian92-test
-  tasks:
-  - release-compile
-  - debug-compile-nosasl-nossl
-  - .latest .nossl
 - name: gcc83
   display_name: GCC 8.3 (Debian 10.0)
   expansions:

.evergreen/legacy_config_generator/evergreen_config_lib/variants.py

@@ -80,13 +80,6 @@ def days(n: int) -> int:
         },
         tags=["pr-merge-gate"],
     ),
-    Variant(
-        "clang38",
-        "clang 3.8 (Debian 9.2)",
-        "debian92-test",
-        ["release-compile", "debug-compile-nosasl-nossl", ".latest .nossl"],
-        {"CC": "clang"},
-    ),
     Variant(
         "openssl",
         "OpenSSL / LibreSSL",
@@ -143,13 +136,6 @@ def days(n: int) -> int:
         ],
         {"CC": "gcc"},
     ),
-    Variant(
-        "gcc63",
-        "GCC 6.3 (Debian 9.2)",
-        "debian92-test",
-        ["release-compile", "debug-compile-nosasl-nossl", ".latest .nossl"],
-        {"CC": "gcc"},
-    ),
     Variant(
         "gcc83",
         "GCC 8.3 (Debian 10.0)",