feat: limit RAM usage in bazel build

[zewenli98]

Description

When building torch-trt from source, the bazel often gets stuck and gets OOM if memory is limited, as it runs 32 actions in parallel. This PR defaults to:

build --jobs=6
build --local_resources=memory=HOST_RAM*.7

It caps concurrent actions and let bazel schedule against a RAM budget. Feel free to tune --jobs up/down based on how much headroom free -g shows during a build.

Fixes # (issue)

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[github-actions]

There are some changes that do not conform to Python style guidelines:

--- /home/runner/work/TensorRT/TensorRT/py/torch_tensorrt/dynamo/lowering/passes/eliminate_sym_min_int64_max.py	2026-07-17 23:16:00.055965+00:00
+++ /home/runner/work/TensorRT/TensorRT/py/torch_tensorrt/dynamo/lowering/passes/eliminate_sym_min_int64_max.py	2026-07-17 23:16:20.971622+00:00
@@ -2,11 +2,10 @@

import torch
from torch.fx import GraphModule, Node

from .pass_utils import clean_up_graph_after_modifications
-

_INT64_MAX = 2**63 - 1
_SYM_MIN = getattr(torch, "sym_min", None)

[github-actions]

There are some changes that do not conform to Python style guidelines:

--- /home/runner/work/TensorRT/TensorRT/py/torch_tensorrt/dynamo/lowering/passes/eliminate_sym_min_int64_max.py	2026-07-17 23:15:58.273713+00:00
+++ /home/runner/work/TensorRT/TensorRT/py/torch_tensorrt/dynamo/lowering/passes/eliminate_sym_min_int64_max.py	2026-07-17 23:16:23.806062+00:00
@@ -2,11 +2,10 @@

import torch
from torch.fx import GraphModule, Node

from .pass_utils import clean_up_graph_after_modifications
-

_INT64_MAX = 2**63 - 1
_SYM_MIN = getattr(torch, "sym_min", None)

[narendasan]

If these are user specific I think we shouldnt check them in. Can be in gitignore We can just use the try-import to pull them in optionally

[narendasan]

Also we should note this in the contributors.md