CI(build-tools): don't install Postgres 14 (#6540)

## Problem

We install Postgres 14 in `build-tools` image, but we don't need
it. We use Postgres binaries, which we build ourselves.

## Summary of changes
- Remove Postgresql 14 installation from `build-tools` image

Dockerfile.build-tools

@@ -73,13 +73,6 @@ RUN curl -fsSL 'https://apt.llvm.org/llvm-snapshot.gpg.key' | apt-key add - \
     && bash -c 'for f in /usr/bin/clang*-${LLVM_VERSION} /usr/bin/llvm*-${LLVM_VERSION}; do ln -s "${f}" "${f%-${LLVM_VERSION}}"; done' \
     && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
-# PostgreSQL 14
-RUN curl -fsSL 'https://www.postgresql.org/media/keys/ACCC4CF8.asc' | apt-key add - \
-    && echo 'deb http://apt.postgresql.org/pub/repos/apt bullseye-pgdg main' > /etc/apt/sources.list.d/pgdg.list \
-    && apt update \
-    && apt install -y postgresql-client-14 \
-    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
-
 # AWS CLI
 RUN curl "https://awscli.amazonaws.com/awscli-exe-linux-$(uname -m).zip" -o "awscliv2.zip" \
     && unzip -q awscliv2.zip \

test_runner/fixtures/neon_fixtures.py

@@ -3075,9 +3075,16 @@ def __init__(
         host: str = "127.0.0.1",
         port: int = 5432,
     ):
-        assert shutil.which(path)
+        search_path = None
+        if (d := os.getenv("POSTGRES_DISTRIB_DIR")) is not None and (
+            v := os.getenv("DEFAULT_PG_VERSION")
+        ) is not None:
+            search_path = Path(d) / f"v{v}" / "bin"
 
-        self.path = path
+        full_path = shutil.which(path, path=search_path)
+        assert full_path is not None
+
+        self.path = full_path
         self.database_url = f"postgres://{host}:{port}/main?options=project%3Dgeneric-project-name"
 
     async def run(self, query: Optional[str] = None) -> asyncio.subprocess.Process: